What is book?
All the positions you currently hold, viewed as one portfolio — traders call it their book.
All the positions you currently hold, viewed as one portfolio — traders call it their book.
Book, explained
Your book is the whole of what you’re holding right now, read as a single portfolio rather than a list of separate trades. When the app says “your book,” it means every open position together — the conviction mix, the total exposure, the P&L still in motion. Closing a trade takes it out of your book and into your history.
Where book shows up in a journal
A trading journal is where this stops being a definition and becomes your own number. sizeforzero computes it from the trades you import or log, alongside the rest of your analytics vocabulary, and every figure in the app carries an (i) that explains it in the same plain English you just read.